Clothing is traditionally used to protect a wearer's body from the surrounding environment, particularly adverse weather, strong sunlight, extreme heat or cold, precipitation, or wind. Clothing is also worn for safety, comfort, modesty, and to reflect religious, cultural, and social values of an individual. Often, clothing is adapted for specialized purposes in which a person wearing the clothing is engaged. Examples of clothing adapted for specialized purposes include a swimsuit, motorcycle leathers, high-visibility clothing, protective clothing, and so on.
One particularly important type of clothing is clothing designed to aid the body's own cooling mechanism. Under certain conditions, a person's body temperature is elevated to a level that is higher than normal. This rise in body temperature may occur because the person is playing sports, exercising, exposed to the sun, or variety of other reasons. To counteract the rise in a person's body temperature, the body begins to perspire, producing sweat to transport excess thermal energy from inside the body to the surface of the skin for evaporation. The sweat's evaporation in turn cools the body. Clothing designed to aid the body's natural cooling process wicks sweat away from the skin for distribution throughout the clothing, and eventually evaporation from the clothing's outer surface. Wicking the sweat away from the skin has the effect of cooling the body because the wicking process removes the thermal energy in the sweat from the body. Clothing designed to aid the body's cooling process in this manner comes in variety of forms and is often designated as active wear, sportswear, stay dry clothing, and the like.
The drawback to the clothing described above is that it relies completely on the sweat produced by a person's own body to facilitate any temperature reduction. Often, however, the body's ability to expel thermal energy through the perspiration process alone is insufficient to reduce the body's temperature to a level that allows a person to achieve maximum endurance during an particular temperature elevating activity. Accordingly, a person must stop or temporarily suspend the activity sooner rather than later to provide the body with sufficient time to cool. For a cyclist, for example, this drawback translates into fewer miles of bike riding. For a road construction worker exposed to the sun, this drawback may translate into less productivity and increased risk of sun stroke.